1. Field of the Invention
The present invention relates to a display apparatus including a display panel and a nonvolatile memory so-called a flash memory, and more particularly, to a driver unit used therein.
2. Description of the Related Art
Recently, as high-level video and information technology as well as multi-media systems have been developed, display apparatuses have become more important. Particularly, flat panel type display apparatuses such as liquid crystal display (LCD) apparatuses, plasma display apparatuses and organic electroluminescence (EL) display apparatuses are lower in power consumption, lighter in weight and thinner in size, and therefore, have been applied to mobile telephone apparatuses or personal digital assistants (PDAs).
Conventionally, display apparatuses including display panels also include mask-type read-only memories (ROMs) for storing initial display data, etc. However, mask-type ROMs have a disadvantage in that their content is determined when they are manufactured, so that the content cannot be changed.
In order to overcome the above-mentioned disadvantage of mask-type ROMs, the mask-type ROMs have been replaced by nonvolatile memories, i.e., so-called flash memories.
A prior art display apparatus including a display panel and a nonvolatile memory is constructed by two individual step-up circuits each for one of the display panel and the nonvolatile memory, since the step-up circuit for the display panel is required to have a small current driving capability and a relatively high output voltage such as 40V to decrease the power consumption, while the step-up circuit for the nonvolatile memory is required to have a large current driving capability and a relatively low output voltage such as 10V. This will be explained later in detail.